基于Adams的摆杆输送机动力学仿真分析

采用Adams脚本语言建模,自动完成摆杆输送机整体系统的轨道、链条、摆杆和工件之间的装配约束和载荷边界条件的设定等.对某卡车白车身涂装过程进行动力学仿真分析,求得系统整体运行时所需的驱动力大小、链节间的相互作用力和进行静力学分析所需的载荷条件等,分析结果可指导摆杆输送机的整体设计.     

单片机混合编程的实现

介绍了单片机的发展,当前应用较多的主流单片机,并对单片机的混合编程实现进行分析与讲解。     

《计算机组装及维护》课程项目教学法研究

项目教学法对于中高职院校培养学生的实际操作能力十分有效,针对《计算机组装与维护》这门课程,通过项目设置、任务分解、组织完成的形式,激发学生学习的兴趣,提高了学生的实际动手能力,取得较好的教学效果。     

A novel vision-based method for 3D profile extraction of wire harness in robotized assembly process

Automating stages for deformable objects in the production line, in which assembling a wire harness into a predefined position is a complex task owing to the specialized characteristics of the objects. Besides a few automatized systems proposed in the other studies to implement this task under simplified setup conditions, a significant portion of this process remains to be completed manually in industrial environments. To construct an automatic wire harness assembly system, the development of a method that can automatically detect the wire harness profile in a 3D environment and, consequently, guide robot arms to implement assembly tasks is indispensable. Therefore, this study presents an approach that satisfies this requirement, which not only proposes a deep learning-based system to detect the wire profile, but also improves the accuracy of the detected results through a correction method according to the depth values of contiguous areas. The verification of the approach in a robot system that highlights its usefulness and practicality demonstrates the potential of the proposed method to replace people and consequently, reduce labour costs in factory environments.     

Simultaneous solving of balancing and sequencing problems with station-dependent assembly times for mixed-model assembly lines

In spite of many studies, investigating balancing and sequencing problems in Mixed-Model Assembly Line (MMAL) individually, this paper solves them simultaneously aiming to minimize total utility work. A new Mixed-Integer Linear Programming (MILP) model is developed to provide the exact solution of the problem with station-dependent assembly times. Because of NP-hardness, a Simulated Annealing (SA) is applied and compared to the Co-evolutionary Genetic Algorithm (Co-GA) from the literature. To strengthen the search process, two main hypotheses, namely simultaneous search and feasible search, are developed contrasting Co-GA. Various parameters of SA are reviewed to calibrate the algorithm by means of Taguchi design of experiments. Numerical results statistically show the efficiency and effectiveness of the proposed SA in terms of both the quality of solution and the time of achieving the best solution. Finally, the contribution of each hypothesis in this superiority is analyzed.     

Teleoperation to robotics at Langley Research Center

A popular conception of the evolution of remote manipulation is a progression from teleoperation to telerobotics and then to robotics. This is logical because in going from teleoperation to robotics there would appear to be a continuous decrease in manned workload, an increase in system complexity, and an increase in the amount of intelligence in the automated system. During the past 10 years NASA Langley Research Center (LaRC) has been involved in all three areas. The decision on which system is most suitable for a task depends not only on the task, but on the allocation of responsibility for intelligence or high level control. The operator may be responsible for all intelligence and control functions, they may be shared between the operator and the automated system, or they may be performed by an autonomous system. This paper discusses some of the experiences in each area in applications related to possible space tasks and some of the lessons learned.     

等温核酸放大技术在重金属检测方面的应用

等温核酸放大技术是一种可以实现重金属污染物痕量分析的高灵敏性检测方法,在分析检测中有着广泛且重要的作用。本文综述了几种不同的等温核酸放大技术及其在重金属检测方面的应用,阐述分析了各方法的检测原理,为之后建立更加灵敏、快速、准确的检测方法提供了参考。虽然等温核酸放大技术目前主要停留在实验室阶段,并且检测目标有限,但是由于该技术的高灵敏性、特异性以及与其他学科紧密的联系性,具有潜在的应用前景。     

ATP-Independent Initiation during Cap-Independent Translation of m6A-Modified mRNA

The methylation of adenosine in the N⁶ position (m⁶A) is a widely used modification of eukaryotic mRNAs. Its importance for the regulation of mRNA translation was put forward recently, essentially due to the ability of methylated mRNA to be translated in conditions of inhibited cap-dependent translation initiation, e.g., under stress. However, the peculiarities of translation initiation on m⁶A-modified mRNAs are not fully known. In this study, we used toeprinting and translation in a cell-free system to confirm that m⁶A-modified mRNAs can be translated in conditions of suppressed cap-dependent translation. We show for the first time that m⁶A-modified mRNAs display not only decreased elongation, but also a lower efficiency of translation initiation. Additionally, we report relative resistance of m⁶A-mRNA translation initiation in the absence of ATP and inhibited eIF4A activity. Our novel findings indicate that the scanning of m⁶A-modified leader sequences is performed by a noncanonical mechanism.     

Synergistic Flame Retardant Effects of Carbon Nanotube-Based Multilayer Nanocoatings

In an effort to develop highly functionalized flame retardant materials, hybrid nanocoatings are prepared by alternately depositing a positively charged polyaniline (PANi) and negatively charged montmorillonite (MMT) using the layer-by-layer (LbL) assembly technique. Carbon nanotubes (CNTs) are employed in polymer nanocomposites as effective reinforcement, where nanotubes are stabilized in MMT aqueous solution. The 3D structure and high density of CNTs deposited in the PANi/CNTs-MMT multilayers produce thicker and heavier coatings in comparison to the LbL assemblies without CNTs. Vertical and horizontal flame testing show that the incorporation of CNTs improves fire resistance. Additionally, cone calorimetry reveals that stacking two nanomaterials (MMT and CNTs) in a single coating shows a significant reduction in peak heat release rate (up to 51%), total smoke release (up to 47%), and total heat release (up to 37%) for the polyurethane foam. The enhancement of flame retardancy is attributed to a synergistic effect; MMT serves as a physical barrier that retards the diffusion of heat and gas. The addition of CNTs strengthens the thermal stability and high char yield. These results, coupled with the simplicity with which the LbL deposition is applied, present a viable alternative to halogen-free flame retardant nanocoatings to natural and synthetic fibers.     

基于偏差向量的机器人装配系统零件抓取精度分析

应用偏差向量描述了影响机器人抓取零件过程的各种误差，提出了计算零件抓取成功性方法，在引入手爪的偏差矫正能力的概念后，建立了确定零件抓取精度的模型，该模型适合于各种零件抓取过程，是研究机器人装配系统的装配精度和装配质量的基础。